The Descent (Neil Marshall – 2005) A-

As a horror movie with genuine dread and terror this works great. It is not about creatures or gore (although you do have those) but about a descent into a deep dark unexplored cave and getting stuck in there. That alone is pretty scary, add to that the dark gloom and the red/green lights from flares and flash lights, the aforementioned bat/humanoid creatures and the distinct personalities and deep secrets of the six spelunking women and you have a hell of a horror film.